Method of making lock nuts



May 23, 1944. B H MOR-rus 2,349,513

' l METHOD oF MAKING Loox NUTS 42 sheets-sheet 1 Filed Jan. 9, 194s rnvVENToR. EENJAM//YHMo/aras BY 5M #Trae/wiwi May 23, 1944. B. H. MoR'rus 2,349,513

v METHOD OF MAKING LOCK NUTS Filed Jan. 9, 1.943 2 Sheets-Sheet 2 INVENTOR. ewfqM//Y/ Maerz/.s

- mentes Mq 2a, 1944 UNrrsD fs'rA'rss PATENT ori-lcs Marilou or Mimmo Loox Nurs Benjamin H. Mortus, Shaker Heights, Ohio. assignor to The National Screw Manufactur- Company, Cleveland, Ohio, a corporation of Application January 9, 1943, Serial No. 471,832

1 claim. (c1.- 1li-s6) This invention relates to a method of forming lock nuts and has for its object to produce a lock nut which has a closer grip on the screw or bolt to which `it is applied and which does less damage to the screw or bolt than the lock nuts now employed.

Still further the invention aims to provide a lock nut which can be used over and over again without impairing the locking action thereof.

More speciilcally the invention relates to a method of forming lock nuts of the castle type the slotted sections of which are bent inwardly to close the slots. the novelty residingv inthe use o! an undersize tap for retapping the closed portion only of the nut.

'I'he invention may be further briefly summarized as consisting in the steps of the im Vproved method which will be described in the specification and claim.

In the accompanying sheets of drawings which show the steps in the lock nut.

Fig. 1 is a side view rod:

Fig. 2 is an end view of the same;

Pig. 3 ls a side view of the slug cold-formed to hexagonal shape:

Fig. 4 is an end view of the same;

Fig. 5 is a side been drilled and formed externally in the usual manner; f

Fig. 6 is'an end view of the same;

I Fig. l is a side view. of the nut after it has been saw-slotted at the reduced end;

Fig. 8 is an end view 4of the same;

Fig. 9 is a `side view of the nut after it has been tapped;

Fig. 10 is an end view of the same:

Fig. 11 is a side view of the nut with the slotted portion pressed closed:

Fig. 12 is an end view of the same;

Fig. 13 isa side view showing the closed end retapped by the use oi' an undersize tap in which operation the closed portion only is tapped;

Fig. 14 is an end view oi the same;

' Figs. i5 and 16 are views on an enlarged scale corresponding to Figs. 1l and 12; and

Figs. 17 and 18 are views on an enlarged scale corresponding to Figs. 13 and 14.

Referring now to the drawings. in the first step of the process or method a slug il, shown in Figs. land 2, is cut from a wire or rod and in the next step it is squeezed to polygonal shape,

set forth in the appended of a slug cut from a round formation of my improved view of the nut after it has in this instance to hexagonal shape, to form a hexagonal blank il as shown in Figs. 3 and 4. These two operations can be combined into one if there is initially employed a polygonal wire or rod.

Next the blank is drilled and is shaped externally to form the nut blank I2 shown in Figs. `5 and 6. In this operation one end of the blank is reduced' in thickness externally, as shown at I3.

In the next operation the reduced end Il is sawed as at Il producing the sawed blank I5, as shown in Figs. 'I and 8. For a Y2 inch nut the sawed slot is approximately nl, inch in width. Next the sawed blank is tapped, producing the blank I6, as shown in Figs. 9 and l0.

In the succeeding operation the sections of the slotted end of the blank are forced inwardly until the sides oi' the slots'engage each other for a substantial part of their length., as shown at I'l in Figs. 11 and 12.

Upto this point the operations are well known and the lock nuts produced thereby are commercial lock nuts well 'known in the art, with this exception that the' slotted portions of the reduced end were not pressed inwardly so as to `engage'each other particularly for a substantial part of their length. However, these lock nuts are not entirely satisfactory because when the sections o! the reduced ends of the nut are forced inwardly, the bore of the reduced end is pressed out of round, and'in the case of a nut having six sections the bore is somewhat hexagonal in shape. The disadvantage of the use of a lock nut of this kind is that it causes damage to the screw or bolt to which it is applied because of its out of round shape.

I have improved the lock nuts of this type by rtapping the nuts at the reduced end only, using a, slightly undersize tap, thus producing the lock nut i8 shown in Figs. 13 and 14, the bore of -this lock nut, as viewed from the end (Fig. 14) being perfectly round in cross-section, Whereas the bore of the lock nut shown in Fig. 12 is out of round.

The undersize tap which I- employ is i'rom .005 inch to .008 inch (more or less) smaller in diameter than the tap utilized to tap the nut shown in Figs. 11 and 12. This undersize tap is shown by dotted lines at i9 in Fig. 13, and it is run into the nut from the larger end so as not to cross the threads of the nished lock nut. 'I'his produces a lock nut which does not damage the screw or bolt to which it is applied and which can be used over and over again, especially as scribed.

In Figs. 15 to 18 I have shown on en enlarged lscale the lock nuts 0T Figs. 11 to l14:. The

dotted line 20 in Fig. 15 represents the outside diameter of the thread of the nut. The dotted line 2| represents the outside diameter oi' the reduced part, and the dotted line 22 represents the l'inside diameter of the reduced part. The distance between the dotted line 23 and the full line 24 in Fig. 16 represents the amount' of dietortion of the sections at the slotted end of the nut prior to the second tapping operation..

En Fig. 17 the line 2t represents the outside diameter of the thread of the mein-part of the .eclr nut and the dotted-line 25 represents the inside diameter of the reduced end after the one tapping operation. By reference to Fig. it will be seen' that this line is perfectly round due to the removal of the distorted portions of Figs. 15 and 16, i. e., the portions between the lines 23 and 24.

While I have shown and described the preferred method of making these lock nuts, I do not desire to be conined to the. precise details shown but nim in my claim to cover elhmodications which do not involve a departure from the spirit and the scope of the invention.

l0 Having thus described my invention, I claim:

The process of making a. lock nut which comprises drilling, lacing end reducing the end of a blank externally et one end, slottng the reduced end of the blank, tapping the blank for l5 its full length se' as to produce e. blank having e.

thread with e uniform pitch from one endof the blank. te other, forcing the slotted sections of the bienk inwardly until they engere each other for e substantiel; peri; of their length,

- emi reteppr'n; the blank the reduced end with an undersize te@g EENJ'AlMIN I. MORTUS. 

